Experience gained from the former uranium ore processing and the remediation of the site in Hungary

Full text: Uranium ore processing started in Hungary in 1962 and was terminated in 1997 on economical reasons. The remediation of the site has started immediately and has been practically finished this year. In the poster a brief overview of the used processes, including the heap leaching will be presented including the overall remediation of the former processing site. The lessons learned both from the processing practice and the remediatation will be discussed, aiming at giving supporting tools for the development of new uranium production facilities. Main lessons are: - for the decreasing of the volume of waste rocks to be remediated the radiometric sorting should be placed in underground if possible, - for the heap leaching reusable pads are recommended instead of permanently expanding heaps. - the high contamination of groundwater around the tailings ponds is the consequence of the inadequate neutralization of the barren pulp - uranium contamination on the heap leaching site is the result of the leakage from the pipes rather than the seepage through the liner. Results of the six years' groundwater restoration practice on tailings ponds site will be also discussed together with the estimation of the decreasing of the concentrations of the principal pollutants in the groundwater in long-term. The presentation will highlight the applicability of the geoelectrical multielectrode measurements for monitoring of the contamination (with MgSO4, NaCl, CaCl2 etc.) of the groundwater around tailings piles. The method has proved to be excellent tool for screening large areas aiming at determining the extent of the polluted area. For the determination of the inhomogenity of the water content in the tailings piles neutron probing method was developed. Results are important for the physical stability analyses of the tailings piles. Results of the run of the experimental permeable reactive barrier (built in the frame of EU-sponsored PEREBAR project) also will be presented. (author)